Comet C/2010 X1 (Elenin) was a comet discovered by Russian astronomer Leonid Elenin on December 10, 2010. Leonid was using a robotic observatory near Mayhill, New Mexico at the time of discovery.

Leonid Elenin

Mr. Elenin is an amateur1 astronomer from Lubertsy City, Russia, near Moscow2. He is a graduate of the Moscow Aviation Institute3, works as a researcher at the Keldysh Institute of Applied Mathematics (Russian Academy of Sciences)4, is married, and speaks both Russian and English. He volunteers with the International Astronomical Search Collaboration5, and runs a website at http://SpaceObs.org. He has had a passion for astronomy since childhood, and studies minor Solar System objects and stars. He has discovered over 10 variable stars (and numerous asteroids), and as of 2010, a comet.

Comet C/2010 X1 (Elenin)

On December 11th, 2010, Leonid Elenin posted news on his website of a "new and interesting object"6 discovered during a "routine survey of the sky on Dec. 10, 2010". The discovery was made at the independent Russian remote observatory ISON-NM, which is located near Mayhill, New Mexico. The observatory is operated under the Russian project ISON (International Scientific Optical Network). His observations were confirmed by Aleksei Sergeyev and Artyom Novichonok of Madinak Observatory, located in the Ukraine.

Initially the comet was thought to be a short period comet, with aphelion near the orbit of Jupiter, and a perihelion inside the orbit of Earth7. However, over a week after its discovery, the Minor Planet Center at Harvard published the orbital elements8, revealing that the perihelion would be near Mercury! It was still unclear as to whether this was a rogue (a one time event) or a periodic comet. Further observations and calculations show that its orbit was hyperbolic, meaning that this is likely its first pass through the inner solar system.

Hyperbolic Comet

According to the JPL Small Body Database9 C/2010 X1 is a Hyperbolic Comet, meaning that it will not return. However, Leonid Elenin has calculated10 that due to perturbations to the comet's orbit from the gas giant planets, that the orbit of the comet would have been modified to a long-period elliptical orbit, and that it would have returned in about 10,000 years.

Orbit

Comet Elenin was in an orbit that is close to the plane of the ecliptic. In March 2011 it was just past opposition11 and about 3 times farther away from us than we are from the sun. Click here for an illustration of the comet's orbit as of March 30, 2011

By September 1st, 2011, Comet Elenin approached the orbit of Mercury, and reached perhelion on September 10th12. In just a little over a month it traveled from the orbit of the Earth to the orbit of Mercury. In late September it was so close to the sun from our vantage point that it was completely hidden. However, it was expected be visible on solar-observing spacecraft such as STEREO and SOHO. It should have been visible in the field of view of the SOHO LASCO C3 instrument between September 23rd and 29th, passing just above the Sun on September 26th, but the images were checked on September 23rd and no sign of the comet was discernible. This appears to support the view that the comet had broken up (see below).

On October 16th, 2011, Comet Elenin would have made its closest approach to the Earth. However, its distance to the Earth will still be huge, nearly a quarter of the distance between the Earth and the Sun. During October 2011, Comet Elenin may become visible in the pre-dawn eastern sky to observers with telescopes.

Leonid Elenin

Leonid Elenin, the discoverer of the comet that bears his name. (C/2010 X1).

Comet Elenin is breaking up

As of September 14th, 2011, reports indicate that Elenin is breaking apart and will not last much longer. See the Universe Today article Comet Elenin is Now Fading Away.

Wild Claims

Instead of being excited about the possibility of a naked-eye visible comet, some people are making some very strange and wild claims about the comet, or about Leonid Elenin. Some people13 are apparently questioning whether Leonid Elenin is even a real person, despite the fact that he is acknowledged as a contributor in various scholarly journal articles since 2009.

The name Elenin is not a coded message.

Several people have posted ideas about the name 'Elenin', where they claim that the name is actually a coded message. For whatever reason, they believe that those evil "powers that be" encode hints in the names of things as a means of communication with each other, rather than taking advantage of encrypted email or even just a phone call. Some of the 'codes' proposed for 'Elenin' are very strange. For example 'ELENIN' means "Extinction Level Event, Nibiru Is Near" to one YouTube poster. Another proposes "Extinction Level Event NINe" implying that there were eight before. bikenbeer2000 proposes one of our own "Expect Little Else, Nutcases Indulging in﻿ Nonsense".

Elenin is not a 'brown dwarf star' or 'black hole'

Brown Dwarfs are not stars14, but occupy the space between really big planets and really small stars. The range of mass for a brown dwarf is between 13 and 8015 times the mass of Jupiter (MJ). In addition, brown dwarfs are about the same size as the planet Jupiter16, and would be as visible as the planet Jupiter is.

Black Holes are stellar mass objects, and in the presence of gas (as in the Solar Wind) they are anything but black. A black hole would be pulling in the gas from the solar wind and accelerating it to near light speed, causing it to blast radiation in X-Ray frequencies as well as infrared and visible light. This would be very visible to every astronomer on the Earth.

If Comet C/2010 X1 was traveling with a massive object, it would be in orbit around that object, like a moon orbits a planet. Otherwise it would simply fall into it. We would see Elenin spiraling around this object in its orbit, rather than the smooth, graceful sweeping path it is taking now. Since we don't see this spiraling effect, Elenin is not traveling with a massive object.

In addition, a massive object would be causing changes in the orbits of planets. In particular, since Comet C/2010 X1 passed close to Saturn, the orbit of Saturn would have been changed. Since Saturn is exactly where it should be, Elenin is not that massive, and it is not traveling with an object that massive.

The Earth will not pass through Elenin's Tail

A common misconception of comets is that the tail streams out behind the comet. Even if that were the case, the images and video above show that we would not pass through the tail. However, the tail of a comet does not stream out behind the comet's path, but rather points away from the sun. As such, the tail will never be in a position to cross the path of the Earth.

Even if the Earth were to pass through the tail of the comet, the only effect on the Earth would be a nice shower of meteors. The Perseid meteor shower occurs every year between August 9 and 13 when the Earth passes through the orbit of Comet Swift-Tuttle. Comet Halley is the source of the Orionid shower in October.17

Leonid Elenin is a real person

Yes, it has been claimed that "Leonid Elenin" does not, in fact, exist, but that instead his name is a 'coded message'.18.

The poster finishes off a list of what they see as 'hints' in the circumstances with the statement:

You know the way TPTB operate. Everything is scripted well in advance and they use Hollywood to drop clues.

Or, it could be that the poster watches too many fictional movies and thinks that they are 'coded messages' from "The Powers That Be".

Various conspiracy theories

One site makes the following claim about Elenin:

So, you are probably wondering, what about the comet Elenin? In early September, the comet will cross earth’s orbit and be between the earth and the sun. Then on September 26, there will be an alignment with the sun, comet, and earth. This could be at the exact time the UN is debating the creation of a Palestinian state! The comet will be closet to the earth around October 15, which is during the Feast of Tabernacles.

Needless to say the site forwards this information as support for their own religious 'end of the world' theories.

Can Elenin (or any other comet) cause earthquakes?

No. Comets can't cause earthquakes. Earthquakes are not caused by celestial objects, or alignments with them, but rather are the result of geologic processes here on (and in) the Earth.

Various claims have been made about the mass of Comet Elenin, or about the mass of an object 'following' Comet Elenin (which apparently is invisible, because zero observations have been made of this object), and various people (including Alexander Retrov) have claimed that C/2010 X1 (Elenin) has caused earthquakes, specifically the February 27, 2010 Mw 8.8 Chile earthquake, the September 3, 2010 Mw 7.0 Canterbury/Christchurch earthquake, and the March 11, 2011 Mw 9.0 Honshu earthquake. However, proponents harp on the 'hits' and ignore the 'misses', a classic example of the fallacy of observational selection.

Here is a list of 7.0 and larger earthquakes that have occurred since January 2010, that are not mentioned.

Official statements on Elenin

NASA on C/2010 X1

Don Yeomans on C/2010 X1

"So you've got a modest-sized icy dirtball that is getting no closer than 35 million kilometers," said Yeomans. "It will have an immeasurably miniscule influence on our planet. By comparison, my subcompact automobile exerts a greater influence on the ocean's tides than comet Elenin ever will."20

NASA's David Morrison on Comet Elenin claims

"The comet never comes close to the Earth, but it is expected to be visible in binoculars during August and October. Part of the Internet chatter concerns its size. Comets are exceedingly small and enveloped in a tenuous cloud of gas and dust, so the only way to be sure of their actual dimensions is to visit with a spacecraft. This means its mass is less than one billionth the mass of the Earth. Needless to say, we will not be aware of the tiny gravitational pull from Elenin."

This is a quote from a David's answer to a question on the "Ask an astrobiologist" page. He has received lots of questions about Elenin as well.

Discovery Space on C/2010 X1

Conclusion

Comet C/2010 X1 (Elenin) is not a threat to the Earth. It is not a 'brown dwarf star', nor is it being accompanied by a massive object such as a black hole or rogue planet. It is behaving exactly as a comet should behave, obeying Kepler's laws of Planetary Motion.